GPS problem with my CPC1100

I have had this scope for about 5 years now. I live in central Texas, currently UTC-5. I have had my scope powered on & plugged in for the better part of 4 days now. It was actually on for 36 hours at one point. I never get a GPS fix and the time is always off by close to 2 hours if I havent used it for awhile. Now that it has been on for awhile, the time will usually be off by about 15 minutes.

I always was impatient and just input my coordinates, date, time on my own and things worked well.

I upgraded my hand paddle about 4 days ago to the latest version and now I cannot find a place to manually enter my lat/lon. I can change the date, time, time zone, but not the location. If I check the location, it indicates that I am in a saved location of 33:50:41 lat & -118:20:17 long.

The date will always indicate February of 2004. I dont remember the exact date.

Does this sound like a GPS battery issue? I am using the Celestron power supply that I got from OPT recently. My original power supply failed about 6 months ago.

I am almost always setup on the same location at our observing site with about 330 degrees of unobstructed view.

I've set my CPC1100 up at a dark site a few times and I don't know what it is about that site, but my GPS always times out and it turns itself off. I can take it home or to my other dark site and it works fine, so I'd suggest you double check it's on.

The battery won't help. A totally dead battery only means the receiver will have to download an almanac from the SVs. It will get a fix, it will just take longer. A dead battery in my NS GPS means it might take 45-seconds to get a fix...and with the weather we've had the last year or two, the battery is often dead.

Suggestions? If the scope hasn't been opened, the first thing to do is do a reset to factory values, re-enter all the vital information, set up in an open, clear area and see if it will get a fix. If it doesn't get one in a minute or three, there is a problem with the receiver, the antenna, or the connections.

Oh...and where has your scope been setup? The receiver will NEVER get a fix indoors.

Just from my own, recent experience with a C11 GPS vs2 scope using a new HC (vs 4.18), when my GPS battery died it would take several minutes before the scope locked on to the GPS sats, then after a 3 star alignment the scope could locate and an object but the tracking was bad, after 30 minutes of use, the scope could not point accurately. After I replaced the GPS battery and allowed the scope to charge the battery for 48 hrs, with out making any adjustments to the HC settings, the time to lock on to GPS sats was very fast, after an alignment (even just a quick moon alignment) pointing was dead-on even after 3 hrs of use and tracking was back to excellent. So, for me, it was worth changing the GPS battery.

I think the newer CPC models have the GPS battery soldered to the GPS module so it may not be an easily fix as with the some of the older GPS models.

I agree Uncle Rod, GPS does not affect tracking. Tracking and pointing accuracy are dependent on accurate date and time. The battery, in addition to maintain the sat ephemerides, also maintains the scopes internal date/time after an alignment, at least with the older NexStar GPS units. No battery, no accurately maintained internal time, degrading pointing and tracking over a short period of time.

With the scope turned off, time might get off. But once you power it up and get a fix, time will be right again sooo...the battery really cannot affect tracking. Not that it would really affect tracking in anyway. Tracking is dependent on _alignment_. As long as the scope knows its current altitude and azimuth, tracking will be just fine. Time doesn't enter into it at all.

Doesn't time affect GoTo accuracy? If the time is off, how will it perform accurate GoTo? It is correct that the mount does not care about current time during tracking but it might care for next GoTo.

Simply set the correct date/time every time you power on the scope and double check location (Lat/Long) and you should be fine.

Peter

Time does not affect go-tos. EXCEPT to planets. If time is GROSSLY off, a planet might be missed, but it will have to be days and days off, not minutes. Again, what matters for tracking is alignment, and that's mostly true of go-to too.

Then what is the GoTo based on? So after successfull star alignments, it must use relative time instead of absolute time. In other words, it probably calculates the time difference between the new GoTo and current location which probably makes sense that the internal time does not matter. Astro-Physics mounts do the same thing by using relative to current position.

First when discussing goto accuracy we need to differentiate between DSO and solar system tracking and pointing capabilities. The tracking and pointing accuracy of DSOs is dependent on accurate sidereal time and location. Solar system tracking and pointing accuracy is dependent on accurate local "civil" time and location.

The tracking of and pointing accuracy to DSOs is only dependent on how well the initial alignment is done (good choice of stars, accurately centered). The local time and date does not affect that. The software in the micro controller (in the HC) maintains local sidereal time (LST) which is derived from the initial alignment and not calculated off of local time ... a real time clock is only a convenience.

An accurate user inputted or GPS derived local or civil time/date/position is important for a) pointing to and selection/filtering of the initial alignment stars and b) tracking of and pointing to solar system objects.

So the the verdict is that the GPS battery has no bearing on the functioning of the scope outside of maintaining the sat ephemeris/faster link with GPS sats. It's ok to have a dead and/or no battery on the GPS module since it only results in slower GPS link; correct?

Nobody actually answered the question proposed by WillieS above, when starting this thread:

"I upgraded my hand paddle about 4 days ago to the latest version and now I cannot find a place to manually enter my lat/lon. I can change the date, time, time zone, but not the location. If I check the location, it indicates that I am in a saved location of 33:50:41 lat & -118:20:17 long".

I have exactly the same problem, my CPC 1100 EdgeHD with Nexstar+ HC has a GPS that does not sync. I will solve this problem someday, but I want to set the location manually in the meantime, however it does not allow me to enter the position manually, be it with the GPS on or off.

Does anybody have the procedures to enter the location manually? They can't be found in the CPC Manual. When I go to Scope Set Up the possibility of changing time, time zone etc is always offered, but never the possibility of entering a location.

A naïve question, particularly in view of the fact that I know very little of the CPC 1100, but if you can bring your Lat./Long. location to the HC's screen and view it, (as you indicate you can), is the first digit in the sequence of co-ordinate numbers not flashing, thereby inviting you to change it ?

Is perhaps any invitation to change, (indicated by the first flashing digit) only evident if the GPS is indeed switched off and you've possibly missed this invitation ?

Are you leaving the GPS enough time to establish your location before trying to align ?

As I said Paulo, I'm not at all familiar with the CPC1100 but just thought a few suggestions might help. Please feel free to dismiss them !

My Nexstar 11 GPS was off by 10-15 degrees when finding north and when slewing to align stars, was off by that 10-15 degrees. I decided to turn off my GPS and instead use the tried and true method of just re-entering my time, date and location if need be. I do Auto Align, level and find north manually and it slews to stars that are around at that time of the night. It works actually faster with me inputting the data manually. Six of one and a half dozen of the other, I say. GPS sounds like a nice advantage, but when the GPS screws up, rather than get frustrated, I just turn it off. It affects nothing for go-to's, and I have no more problems at all.

Does anybody have the procedures to enter the location manually? They can't be found in the CPC Manual. When I go to Scope Set Up the possibility of changing time, time zone etc is always offered, but never the possibility of entering a location.

Thanks for the support.
Paulo

Paulo is right. We need an answer on this. I don't want to compromise a nights viewing at some remote location when my gps won't link. I have read lots of folks posts where they mention manually entering Lat & Long, but I wonder if they are using the pre-nexstar plus hand controller.? I like paulo have tried everything I can think of, and cannot find a way to manually enter, or edit L & L in the nexstar plus.